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Tank Coating Repairs

Discussion in 'Technical Discussion' started by Ken Bracewell, Oct 20, 2008.

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  1. Ken Bracewell, Oct 20, 2008
    #1
    Ken Bracewell

    Ken Bracewell Senior Member

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    We are in the final stages of our Lloyd's special survey and have learned that we need to blast and re-coat our black water tank.
    It is obvious that this has never been done as there was no access to the tank other than the inspection (man-hole) cover at the forward end of the tank. The tank was built integrally by welding over the frames, so we had to cut through 5 frames/baffles while also maintaining the structural integrity.
    After accomplishing this, I thought we had cleared the toughest hurdles until I received the quote to sand-blast and re-coat the tank with DEVRAN 133 epoxy. Since it is estimated to take 2-men approximately 5 days, I was flabbergasted to get a quote for $18,000 (the tank has already been accessed and cleaned at a cost of about $10,000). I've since learned that there is basically a monopoly, of sorts, in South Florida on this type of work.
    While I very much like the contractor doing the work and don't doubt their ability to do it well, this still seems like a very steep price. Does anyone have a suggestion for a tank contractor in Florida who would be capable of handling this?
    Thanks in advance!
    Ken
  2. Ken Bracewell, Oct 20, 2008
    #2
    Ken Bracewell

    Ken Bracewell Senior Member

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    On Second Thought...

    A re-assessment of the job has yielded a discount. Proceeding tomorrow. :cool:
  3. Castlerock, Oct 20, 2008
    #3
    Castlerock

    Castlerock Senior Member

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    That was fast, did they read you post?
  4. Fishtigua, Oct 20, 2008
    #4
    Fishtigua

    Fishtigua Senior Member

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    Ken,

    I feel your pain. I think we've all had qoutes where your jaw hits the deck.

    Once I ran a 80'footer were the exhausts ran all the way to transom so that when at anchor, a Slap, Slap occurred in the aftcabin. The owner, who lived aboard 6 months of the year in the aftcabin, asked if we could do something about it.

    So, while out of the water, I asked the yard manager to give a quote for cutting off the side pipes and making some little downturn exhausts amidships.

    An utterly HUGE price was named.This, over 5 hot, sweaty and very sweary days, was negociatied down to a reasonable price. Then, this is the killer, the manager asked if we wanted the other side done as well. :eek:

    Fish
  5. Ken Bracewell, Oct 20, 2008
    #5
    Ken Bracewell

    Ken Bracewell Senior Member

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    No... I think that after I told them Friday that we would be looking for other quotes, they spent a little time re-evaluating the job.
    We'll all end up happy in the end.
  6. Codger, Oct 20, 2008
    #6
    Codger

    Codger YF Wisdom Dept.

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    "we had to cut through 5 frames/baffles while also maintaining the structural integrity."

    How did you maintain structural integrity? 5 frames must cover a fair stretch.
    Temporary bracing?
  7. K1W1, Oct 20, 2008
    #7
    K1W1

    K1W1 Senior Member

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    Hi,

    I don't really understand the description of the tank arrgt either.

    Ken- Was this tank built in the boat at NQEA from new?

    It is std practice in metal boats to have frames in the tanks, baffles are welded to the ships side and to the tank top.

    A common method to blast out tanks is to cut a hole from the outside do the blasting clean it up weld the hole and re paint it all. I guess it depends how big your tank is if a man couldn't get inside and work to do the painting then opening up the top seems like the only proper way.
  8. Ken Bracewell, Oct 20, 2008
    #8
    Ken Bracewell

    Ken Bracewell Senior Member

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    The tank isn't very large. The max dimensions of the "triangle" we cut out was 13"x24" and we maintained the scantling dimension all around. Lloyds gave their approval to this method.
    The tank is original. The tank is located between the engines, so accessing from the sides is not possible without compromising the engine stringers. It would also be near impossible to access the top without hacking out a plethora of plumbing. That leaves cutting them from the underside which would still necessitate putting a man inside the tank in order to weld the inner seems on the hull plate.
  9. K1W1, Oct 20, 2008
    #9
    K1W1

    K1W1 Senior Member

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    Hi,

    That's a pretty stiff part of the boat as well so you could take out a lot of the tank material and still maintain your structural integrity,-- As long as it was all put back in!